


The Locket

by BasicallyFrisk



Category: Undertale (Video Game)
Genre: Adorable, Alphys - Freeform, Cute, F/M, Female Frisk, Flirty Frisk, Fluff, Frisk - Freeform, Multi, Older Frisk, Possessive Sans, Sans - Freeform, Smut, Toriel - Freeform, Undyne - Freeform, Wet Dream, frick me up, isaidmaybe, maybeeventualsmut, more tags to come, undertale - Freeform
Language: English
Status: In-Progress
Published: 2016-03-20
Updated: 2016-04-13
Packaged: 2018-05-27 23:31:10
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 5
Words: 6,112
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6304510
Author URL: https://archiveofourown.org/users/BasicallyFrisk/pseuds/BasicallyFrisk
Summary: <blockquote class="userstuff">
              <p>In the underground when a monster turns eighteen, their soul begins to change. They long for their second half, their soulmate. Other available monsters develop a thirst for the newly matured being. They then go on dates with every available bachelor or bachelorette in order to find the perfect companion. The best part? Frisk's eighteenth birthday is tomorrow. Hehehehehe he </p><p> </p><p>Heh</p>
            </blockquote>





	1. Birthday Shopping

Hi guys! This is my first Undertale fanfic and I'm really nervous about posting it. But I feel like it has real potential and I wanted to share it with you guys. This fic will be about Frisk and Sans and how when she finally turns eighteen, a sudden lust develops in Sans, and how they work everything out

If anyone wants to edit, write puns or even co-write this fic, pm me or comment!

Also sorry it's short, it's kinda just a taste of what's to come!

 

Sans POV~~~~~~

It had been years since the barrier between the surface and the underground had broken, and Frisk had been the reason why. Frisk, the seventh human to fall down Mount Ebott. Frisk, the reason humans and monsters had been reunited. Frisk, the reason Sans has been so happy. Frisk, his best friend. HIS best friend. He often pondered what would have happened if the two hadn't met, but he shuddered at the thought of a life without her. She has filled a void in him and Papyrus. She gave the feeling of the last puzzle piece being added to the never ending puzzle that was the Skeleton Brothers.

Sans had been shopping for a gift to give to the little kiddo, for tomorrow was her 18th birthday and Sans, being the procrastinator that he was, waited until the last minute to purchase a gift that was special. He could almost hear the shouting of Papyrus if he found out Sans was out shopping the day before,"LAZYBONES! WHY HAVEN'T YOU BOUGHT THE HUMAN A PRESENT YET? ARE YOU ANGRY WITH HER? DID YOU TELL HER ANOTHER HORRIBLE PUN AND SHE TOLD YOU THAT YOUR FRIENDSHIP IS OVER? DO NOT FRET, I , THE GREAT PAPYRUS WILL COOK YOU A NICE MEAL OF SPAGHETTI!"

He walked into a cute store that had a ton of outfits and jewelry for women, and when he started looking through each section, he realized how lost he was in the sea of estrogen and perfume. He shook his head in embarrassment. He didn't even know what size clothes she wore. This was gonna be useless.

He finally decided on moving on and stopped by a cute antique store on the corner of the street. He shrugged thinking,"maybe I could find something in here?"

He took in a soft breath and started looking around, noticing how the shop smelled like old books and cookies. A comforting scent. It reminded him of visiting Toriel's home when he would pick Frisk up for their sleepovers with Papyrus. His eyes drifted around, thinking of the hundreds of times Frisk would fall asleep in his arms and how a tiny drop of drool would slowly droop down as her breathing slowed. He had become accustomed to her embrace and wasn't fazed when he realized he had been thinking of the human again. She was almost always on his mind anyways.

'My best friend. Mine.'

His eye sockets paused on a beautiful heart shaped locket that lay on a pedestal with a glass cube surrounding the lovely necklace. He knew, he instantly knew. It screamed Frisk, and he had to get it for her.

He cleared his throat(lol wut) and walked up to a quiet old woman who was behind the cash register.

"How much for the locket?" He smiled with a wink, trying not to sound too interested.

"80 dollars, it's vintage," she cooed (it was a really nice necklace). 

"60 and we have a deal," he bargained. Although he had brought 80 dollars with him, he suddenly was in the mood for a nice cream, and 80 was steep, even for a necklace of that beauty.

"You got a deal, son." She smiled as he handed her the money and waved a goodbye as he left the store.

He opened the locket and thought of what he could put in it to make it more special. Something personal, something unique. Then an idea popped into his head. He concentrated and a wisp of blue magic floated lightly in the sky. He softly guided his magic into the heart shaped locked and shut it lightly. Then another wisp fluttered by and sealed the locket tight.

"Frisk will love this gift," he chucked softly, smiling.


	2. Dreams and Nightmares

 

Sans strolled out of the antique shop as he settled the locket into his sweater pocket. It radiated with his cyan magic and he grinned, he was actually proud of his gift. He couldn't wait to unveil his present to Frisk and, maybe to show her how much he cared, he would award it to her before everyone else showered her with their own gifts. He dashed along, looking forward to the beaming smile on her face once he placed the delicate necklace on her, on its new home.

Frisk POV~~~~~~~~~~~~~~~~~~

_Frisk sat up groggily and glanced around her as she tried to rub the sleep from her eyes, noticing she had fallen asleep on Sans and Papyrus' couch again. The small house was eerily quiet, like seriously. She hauled herself into the kitchen and observed the state of the open area while searching for any signs of life. There was just a big heap of pots soaking in the sink, all caked with leftover, stale spaghetti sauce. There was a neon sticky note attached to the fridge that immediately caught her attention, scrawled in the unmistakable handwriting of none other than the Great Papyrus:_

'HUMAN! I AM SORRY TO INFORM YOU THAT FOR SOME REASON THERE IS NO MORE SPAGHETTI SAUCE! I KNOW, I'M SHOCKED TOO! SO I AM OFF TO GO BUY SOME MORE! IN THE MEAN TIME YOU CAN HANG OUT WITH SANS IF HE ISN'T BEING A LAZYBONES AND STILL SLEEPING! BE BACK IN A JIFFY! -P.S. HAPPY EARLY BIRTHDAY!'

_Frisk smiled softly and peered up the stairs, wondering if Sans was awake. "Sans?" she purred, bounding up the stairs. No response. She tapped at his door and proclaimed in a sing-songy voice, "bonehead wake up!"_

_Frisk felt a cool puff breath on the back of her neck and froze. Her own breath hitched as she whirled around to meet the eye(sockets) of Sans. A hint of a smirk played on his lips._

_"Hey..." she whispered._

_"Hi.." He cut himself short. Sans could feel her face inching ever closer to his. _"Frisk I don't thin-" Her lips were already nestled against his as she enveloped her arms around him. He forced her back, "Frisk what the hell!”__

_"I love you Sans... I love you."_

_His eyes briefly flickered in confusion just before an overwhelming eagerness consumed his entire existence as he pinned her into the wall and kissed her roughly._

Frisk jolted awake with a loud thud that was proceeded by an embarrassingly high pitched squeak when she realized she had rolled off the bed and was greeted face first into a wad of rather grubby socks that were tossed onto the floor. It was a dream. Frisk flung her head up and huffed, blowing a mass of knotted hair away from her face. She scanned her surroundings and registered that she had been sleeping in Sans' room. She blushed slightly at the idea of being in the very room that belonged to the one from her dream and quickly scrambled to her feet, kicking a few of the socks away from their assemblage in her haste. Frisk has been having an innumerable number of dreams involving Sans lately, some cute and some really dirty. She had always wondered if he had a...

Her train of though was diverted when she noticed a wisp of blue magic in the middle of the room and suddenly Sans appeared before her, the man of the hour.

"Hey kiddo gue-"

"I'm not a kid anymore Sans,” Frisk huffed, rolling her eyes. Her dream was momentarily forgotten as annoyance seeped into Frisk's thoughts. “Tomorrow is my eighteenth birthday. Ring any bells?”

Sans gulped when the notion hit him. The kid was turning eighteen. There would be guys and girls pawing all over her, trying to determine who was worthy enough to get in Frisk's pants. Sure they make the whole ordeal seem innocent enough, nothing more than harmless puppy love fun, but Sans wasn't a halfwit. He knew that all it took was one wrong move and Frisk would end up in the arms of someone else. However, despite image of his ( _his_ ) best friend falling for another monster and leaving him behind making him, somehow, physically nauseous, it actually wasn't his most prominent fear. He was more afraid of what _he_ might try to do when the ever approaching day came around. It wasn't like he didn't want to pursue her- He just didn't want to leave their friendship standing in irreversible shambles because he did something idiotic, like making a pass of his own. At least if Frisk ended up with someone else, they would still be friends; it may not be exactly the same but they would still be friends, their ever resilient bond making sure of that. But if Sans messed up, if something went wrong, if it didn't work...well, somethings like that can't be repaired.

_Fuck, it's tomorrow..._

'Too many thoughts.' Sans groaned and flopped back onto his lumpy mattress, half the sheets sprawled across the floor in a haphazard mess from when Frisk took her tumble. Because he was still preoccupied, swimming against the current of emotions that had suddenly flooded his mind, Sans had failed to notice the light shuffling against carpet and the slight shift and creak of the bed before feeling Frisk burrow at his side, resting her head on his shoulder.

"Sans?" Two bright brown eyes peeked up at him, softly studying his features.

"Hm...yeah?" he mumbled through his haze, still completely stupefied over his situation.

"Do you think could explain to me what will happen when I turn eighteen?" Frisk nuzzled closer to Sans, a wispy giggle escaping her when she earned a soft kiss to her forehead. “It can't be as big of a deal as everyone is making it out to be.”

"Well, Frisk, when a monster turns eighteen, their soul begins to change. It becomes restless. It feels empty, and then the monster feels, in fact, needs a second half, a soulmate."

Frisk furrowed her brows, ready to point out the obvious flaw. "But I'm not a monster..."

"You are the exception. You've been eating monster food; Papyrus and I have used our magic to heal you. Your soul... it's not completely human anymore. It hasn't been for a while. You see, for most humans, they long for a partner far earlier than monsters, usually around the time when they start going through puberty. So that's why when you were thirteen, you started having feelings for monsters. They were not full on crushes, but the human part in you was showing."

"So why do monsters have to wait till they are eighteen?"

“It's said that when the monster race was created, that the very essence of our beings, our souls, were divided. Two seemingly separate individuals bound together by the same soul. In a universe as vast as ours it's easy to think that, though we may share the same soul, most of us will never find our other half.” Sans then grasped Frisk's hand, lightly running their thumb over the back of her hand before wrapping their pinkies together in a firm link. With a small smile he continued. “Though, because of our magic, monsters were able to create an invisible bond, a string, to our soulmate that connects us to one another. No matter what, through time and space, it will never break. Monsters wait until they are eighteen because that's when we fully mature and our souls start to seek the one we are connected to. To be honest, I don't specifically know why eighteen was the special age chosen,” Sans shrugged. “It was reason was most likely lost in transla-”

"Sans- I love you," she blurted out. "I t-think you are my soulmate.."

Sans froze and tried to brush it off chuckling softly. "Ha, kid, y-you really know how to pull my leg.." he stuttered detaching half his leg and waved it around. He immediately regretted that joke.

**Notes for the Chapter:**

> HEY GUYS! Chapter two is finally up! I hope you guys are okay with that cliff hanger, it just felt right! Okay wildlittleinferno and I are co-writing this book and I am so lucky to have someone who can make this fan fiction 10000x better! 
> 
> Xoxo Basically Frisk
> 
> Note from wildlittleinferno: Due to some unfortunate circumstances, this fanfiction will be on a mini hiatus. BasicallyFrisk had some personal matters to attend to and won't be able to communicate with me give or take a week. However, once they return everything should get right back on schedule. Thank you all so much for the comments and kudos, we really do apericate it!


	3. Regretted Words

Self-loathing. Instant regret. So, so much stupidity.

'Really?' Sans concluded that this was, without a doubt, the most absurd and ridiculous thing that anyone could have accomplished in this moment. ' _Really_?!'  
  
Frisk gaped at Sans in astonishment and humiliation as a billion varying thoughts engulfed her mind. Was this funny to him? A big joke?

“I-I'm-not joking Sans,” Frisk uttered quietly, striving to stay as calm as possible but falling short as she felt anger seething in her chest. Why? Did Sans not like her that way? Did he think he was better than her just because she's human? Then, a dreadful inkling seeped into her head and she felt the most putrid pang of jealousy she had ever experienced. There was no reason for it. She was acting irrational and she was very well aware of it but Frisk couldn't evade the envy clawing at her throat. “Is there someone else?” Frisk mumbled, regretting even asking a question she knew the answer to. She felt herself snap.

“Listen Fris-” Sans begged feebly, hopelessly trying not to upset his best friend more than he had already done.

“NO YOU LISTEN. YOU TELL ME RIGHT NOW WHAT-WHO HAS YOUR HEART?”

There was a prolonged silence. “No-nobody.” Sans felt his sins crawling up his back.

“Y-you hesitated.” Frisk could feel her eyes watering, hating that she had even said anything in the first place.

“You won't like the answer.”

“Tell. Me.”

“Are you sure? You won-”

“JUST FUCKING TELL ME YOU COWARD!” Frisk immediately morned the words that flew out of her mouth. Sans' left eye lit up vivid cyan for a split second and the next words he would declare would be the death of their friendship, they both knew it.

“Toriel.”

Sans could see red overwhelm Frisk's face and tears collect in her eyes. He could see her struggle internally for composer and then failing as a sole tear gradually dripped down her face before she turned away from him, a slight sob escaping her lips. Alarmingly detached from her surroundings, Frisk stiffly stood and soundlessly walked out of the room, grabbing the edge of the door before slamming it shut, the resonance echoing throughout the house. She bolted down the stairs and out the door towards the only person she believed she could find solace in. Monster Kid.

\-------------  
  
Frisk rubbed her numb hands against her arms, trying to create friction as she felt a bitter gust of wind rushing through her frame. She shivered defenselessly as she watched the nipping air form a blanket of pink over her bare skin. She realized that she had foolishly stormed out into the snowy street in only a tank top and shorts, but she didn't stop. She was Determined. Determined to make Sans pay for his rejection. Determined to make Sans jealous. His words rang in her mind as she felt her tears clouding up her vision, leaving her stumbling along with no direction toward Monster Kid's home. She remembered it was all the otherside of Snowdin. After what seemed like hours of crying and aimlessly walking, Frisk staggered up the steps to Monster Kids' house. It was a small house, two tiny bed rooms and one bathroom, in the place of Undyne's previous fish shaped home. Frisk knocked lightly and mumbled, "please let me in."

No answer.

Her fingertips were turning blue and they glistened with gentle snowflakes. She felt lightheaded and could feel her tears freezing on the spot, touching her cheeks. Frisk had ceased her shivering, the frigid atmosphere building up against her body, forging the feeling of fire submerging her skin.

"M-monster Kid... P-please." She stammered over her tongue, sagging her head against the door and felt a wave of fatigue sweep over her before loosing all feeling in her body and passing out.  
\-------------  
Sans was full of confusion and guilt; what he said wasn't true, not really. Toriel and Sans were only friends and, although he never wanted to hurt Frisk, he knew she would hurt him. _Sans_ _was_ _still_ _out_ _for_ _himself._

Sometimes he wished he did love Toriel. Sure Frisk was the girl of his dreams, but keeping someone that remarkable takes work, effort, and can frequently lead to a lot of complicated circumstances and feelings. Toriel was comfortable; warm and homely. She was never dramatic. Frisk was always dramatic. _Why did she always have to be so gods damn dramatic?_ Toriel was kind, but so was Frisk. Frisk was also passionate and fiery. She was determined, full of love, and got along with everyone. Frisk was perfection. But Frisk was too good for him and once she turned eighteen she would find someone better, someone who didn't wear hoodies everyday or someone who didn't walk around in pink slippers constantly. _Sans you fucking loser._ Sans continued to berate himself, face dug into the palms of his hands. He could feel his eye start radiating an intense shade of cyan and orange, the scorching pressure licking up his hands.

Frisk is better off without you.

All of a sudden he felt a heated, almost searing sensation in his right pocket.

The locket.

It was glowing a brilliant blue and as he inspected closer he saw Frisk. Frisk, laying motionless on the ground, nearly dead. Instinctively, Sans jolted off of his position on the bed. He knew he had to help her. He had to. He had to. His eye proceeded to glow its bright cyan as he grabbed warm clothing, a wool hoodie and a warm knit beanie. In a blink of an eye Sans was right by her with all the necessities and began to heal her with his magic. He returned warmth to her frozen body and bundle her up, shoving the hoodie over her torso and making sure the beanie he brought covered her ears. Before he could do anything else, Monster Kid opened the door, coming to investigate the ruckus on his porch. His eyes widened, surprise and panic flickering in them. He looked extremely guilty.

"Ohmygosh how long was she out here for?"

"Hours I'm guessing! Where the fuck were you?" Sans shot a bone-chilling glare in the direction of Monster Kid. He massaged his hands up and down Frisk's arms, striving to keep his hands occupied so he didn't do something nonsensical...like killing this _idiot_ who couldn't even open the door for Frisk. He had basically left her to die.

"I was playing a video game! I didn't hear her, I swear! I'm so so sorry." Monster Kid felt like breaking down under the hateful daggers Sans was throwing at him. He sighed, failing at keeping the guilt at bay, and looked down, feeling a choking grief building in his chest. “Is she...” he breathed, barely audible. Frisk began to grumble as Sans held her in his arms, nuzzling toward the heat Sans was providing her.

"She's waking up.." Monster Kid beamed and exhaled in relief as the pressure subsided from his chest. Before Monster Kid could say anything else, Sans had disappeared, and Monster Kid peered around in bewilderment, eyebrows pulled in confusion as Sans vanished from existence.  
\---------  
Groggily, Frisk slowly opened her eyes, focusing her gaze on the face of a pleased looking Monster Kid. He had given her warm clothes. He had saved her.

Her heart danced as she surveyed the warm affection residing in his eyes as he knelt down beside her. Maybe...maybe she could fall for Monster Kid?

"Monster Kid... We need to talk."

She smiled when he chuckled. “Frisk you are ever resilient! You are the only person I know who can collapse from the cold and act like it was nothing.”

Frisk giggled.

Maybe dating him won't be so bad.

**Notes for the Chapter:**

> IM SO SORRY FOR THE WAIT! I hope the chapter was worth the wait! Do any of you guys like the song Blue Lips? If you do I love you.  
> The actual next chapter will be frisk turning eighteen and Sans might have a little too much fun ~BasicallyFrisk
> 
> Wildlittleinferno: *waves* Hi!


	4. The Kiss

**Notes for the Chapter:**

> Holy crap! Over 1500 hits! You guys are so awesome and you are the reason we write so often! I hope you guys enjoy this chapter, I know it made me squeal at least 10 times throughout the whole chapter :-) enjoy! ~BasicallyFrisk

Sans teleported back into his empty room. He paced back and forth, silently fuming and eventually he sighed as he rubbed his phalanges against his skull, frustrated at himself, frustrated at everything. 'You fucking coward, you _ran_.'

In the distance he heard the distinctive rattling of pots and pans, Papyrus enthusiastically chattering away about something (Sans would put money on it probably involving spaghetti), and the soft laughter of Metatton as he listened intently. God they were so disgustingly cute. Sans envied it. He remembered the day Papyrus turned eighteen, vividly. Mettaton was the first person at the door that very morning with a bouquet of spaghetti roses (they were pretty impressive) and an elaborate homemade card in an elegant script that read, “You're not just any Cool Dude, You’re MY Cool Dude xoxo.” And that was it. It was sweet and simple, going against Mettaton's usual flamboyant style, but it was exactly what Papyrus wanted and he was on cloud-nine as he welcomed in Mettaton's advances. He knew from the get-go that Mettaton was his soulmate, there was no argument and no second thought. The two embraced and then proceeded to go up into Papyrus’ room and...er- well merged souls. Sans shivered as thought about Frisk, thought about them being together in such an...intimate manner. He could imagine leading her up to his room and them laying on the bed as they kissed, slowly undressing, her soft, supple skin...- he was interrupted by a forceful thwack at the door.

“SANS I KNOW YOU ARE IN THERE! ARE YOU OKAY? I’VE BEEN CALLING YOU DOWN FOR DINNER FOR AGES! IS THE HUMAN WITH YOU? ARE YOU GUYS DEAD?...I HOPE NOT! OR ARE YOU GUYS IGNOR-” Sans unfastened the door leisurely.

“Frisk isn’t here,” he snarled, going to slam the door shut when a large metallic hand caught the door.

“Sans! Don't talk to your brother in that tone. Where is my beauty then?! She promised that I could dress her for tomorrow!” Mettaton dramatically posed then turned to Sans, “where is my beautiful human Sans?”

“Couldn't care less.”

“Well that's rude. Sans, what happened?”

Sans rolled his eyes. “Nothing, nothing happened.”

“SANS, I AM YOUR BROTHER AND THEREFORE I KNOW WHEN YOU ARE LYING! DID YOU MAKE HER UPSET?”

“You could say that.”

“WHERE IS THE HUMAN SANS? METTATON IS SO EXCITED TO SEE HER AND GET HER READY FOR THE EXCITING TRANSFORMATION TOMORROW!”

“Don't remind me..”

“YOU HAVE SUCH AN ATTITUDE TODAY! SANS I SWEAR IF YOU DON'T TELL US RIGHT NO-”

“She's with Monster Kid.”

“What is she doing there?” Mettaton questioned.

“No idea,” Sans lied. “She just got up and left.”

“FANTASTIC SANS! LET'S GO AND GRAB THE HUMAN!” Papyrus exclaimed, grabbing Sans and dragging him out the door and towards Monster Kids house.

~~~~~~~Frisks P.O.V~~~~~~~~~~  
"Welcome to my humble abode." Monster Kid beamed from ear to ear as he tenderly grasped at Frisk's hand and escorted her to his living room, his giddiness was almost palpable as he heard the faint pitter-patter of Frisk's steps when she accompanied him willingly."So, Frisk, what did we need to talk about? Seemed pretty important considering the condition I found you in." Frisk felt a tad bit of shame as she interlaced her hand to his tail tightly as he spoke. Sans was still fresh in her mind and she felt as if she was being disloyal to him just by residing in the company of a guy who wasn't Sans. Monster Kid, unaware of her inner dilemma, flushed a rosy pink at Frisk's advances, only furthering his confidence.

"Sans." Just stating his name aloud reminded Frisk of why she was here in the first place, rage once again bubbling through her veins.

Monster kid's face fell, all traces of confidence perishing. Another man's name was definitely not what he wanted to hear in this instant, especially not Sans'."W-What...” he cleared his throat, suddenly nervous, “what about him?"

Frisk's pent up anger and humiliation regarding her circumstance with Sans began to spill over in the form of nasty remarks and swears."He's a jackass! A fucking asshole! Did you know that he and Toriel are dating? Fucking _dating_. Can you believe that?! That bastard didn't even have the audacity to tell me! He's a coward, a fucking no good coward who has been leading me on for years.."

"Hmm...wonder what that feels like..." Monster Kid griped sarcastically, but Frisk didn't seem to notice, she was too entranced in her rant.

"...and I just always feel like second choice!"

"Join the fucking club," MK mumbled, Frisk heard it this time.

"What was that?" Frisk breathed mutedly, her voice was full of shock and laced with uncertainty. She turned her head to look directly at Monster Kid, her eyes wide in disbelief.

"You heard me. I said join the fucking club! Jeez Frisk, you always choose Sans over me, and now that you feel rejected you come running back to me! You _always_ do this! Whenever you guys fight or when he's not around to keep you entertained are the only times you come to me! I'm always second choice! Always!"

Oh.

Frisk wanted to throw up, she wanted to scream and cry and claw at her skin. She needed to suffer. Frisk felt disgusting, she felt like scum of the earth. She couldn't believe she could ever hate herself more than she did at this moment. There was no way around it, she knew she often used Monster Kid as her own personal Sans punching bag. Frisk recognized Sans was not the biggest Monster Kid fan so, of course, she used that to her advantage and he was the first person she went to when she wanted to make Sans angry. It only made matters worse when Frisk learned of the crush Monster Kid had on her and she enjoyed the attention she received from him when Sans was unable to. But Frisk always assumed it was harmless, that the crush was nothing but a microscopic thing, _it would go away and they were just having fun_. But as she gazed at Monster Kid's enraged face as hot tears streamed down his chin, she finally registered that it wasn't nothing. Frisk squeezed her eyes shut as she felt her own tears gathering quickly. She had to make it up to him. She needed to show him what he meant to her, to show him that he has and always will be important to her. To show him that he mattered. No one deserved the treatment she was giving him.

"No,” she opened her eyes to look up at Monster Kid, her vision blurry with swarming tears, "No you're not. You're amazing, you matter. You always matter. If you were my second choice would I do this?" Frisk studied at Monster Kid's face closely for a moment as she took a breath to steady herself and leaned in. Monster Kid bit his lip as wonderment flooded in his eyes, breath harsh against his tears as he gradually leaned in too. As their lips grazed together, the front door carelessly swung open, no manners being displayed as Mettaton, Sans, and Papyrus all came sauntering into the living room. Their jaws dropped at the view presented itself to them. Mettaton smirked, looking pleasantly amused. Actually, he looked fucking ecstatic, while Papyrus looked around the room, at anything that wasn't the couple in front of them as a bright orange blush stained his cheekbones. Sans looked furious, murderous even.

"Frisk, darling, I didn't mean to interrupt this.. saucy get together,” he wagged his eyebrows,”but you need to come with us sweetheart. You need to rest for tomorrow's big day!" Mettaton purred, hauling Frisk out of Monster Kid's house, not sparing her time to wave a goodbye, and towards the riverboat.

A three minute row down the stream felt like three hours as the four of them all crowded onto the boat with the Riverwoman(?). Sans situated himself across from Frisk. Frisk felt a flourish of shame when her eyes met with Sans' empty, dark ones that seemingly radiated annoyance and exasperated anger. She tried to explain herself, opening her mouth, but she couldn't speak against her heavy tongue. Frisk just shook her head and quickly screwed her lips tightly together. She didn't have to explain herself to him, he was dating someone else, but the look he was throwing in her direction was making her thoughts run wild for the entire boat ride. Did he hate her? She wouldn't be surprised, she hated herself right now, for more reasons than one. Was he actually jealous? No, she reminded herself again that he has someone else. Was he disappointed in her? She knew he really couldn't stand Monster Kid. Frisk could feel herself blushing deeper and deeper under his unwavering, burning gaze. Tomorrow was gonna be a long day.


	5. Happy Beginning

**Notes for the Chapter:**

> Thank you so much for all the hits and Kudos! Don't forget to comment if you like the chapter!

 

 

 

 

 

 

> (Warning the chapter after this one has a lot of smut so beware)

The riverboat ride was intense, drawing out perpetually long. Sans was dangerously close to vaulting himself into the water below them. It would be more enjoyable than watching Frisk stare at the boat under her feet and struggling to comprehend what internal war was battling inside her head. On one hand, he wanted to take her in his arms and kiss her, to comfort her and to tell her what an idiot he was, but on the other he wanted to drown her for kissing another monster. _Really,how could she do that to him?_ Sans exhaled shakily as he settled on watching his leg anxiously bounce up and down _._ He could already predict that tomorrow was going to be the worst day of his life. Sans pulled himself out of his thoughts when the boat lurched to halt and noticed they were _finally_ in Hotland. As they all took their sweet time getting off the boat, Mettaton took the chance to brake the awkward silence.

"Now Frisk, I know you would expect to sleep in your own bed tonight but after tonight's events I would feel more comfortable if my beauty would stay at Alphys' lab."

Frisk groaned, childishly stomping her foot in protest. "But Alphys always makes me sleep on the couch!"

"Nonsense! For tonight, AND TONIGHT ONLY, you and Sans may sleep in my bed at the lab while Papyrus and I sleep on the couch," Mettaton said slyly, pretending to be examining his nails. Frisk's face turned a bright shade of pink at the notion.

"I-I don't think that is a good idea, I can just sleep on the floor," Sans nonchalantly mumbled. That was the first time Frisk had heard Sans stutter over his words.

"NONSENSE HUMAN! YOU DONT MIND HAVING SANS SLEEP IN YOUR BED TONIGHT? RIGHT? IT'S NOT THE ABSOLUTE FIRST TIME YOU GUYS HAVE SLEPT IN EACH OTHERS ARMS AND I CAN GUARANTEE IT WONT BE THE LAST! IT WILL ALSO GIVE YOU TWO THE CHANCE TO GET OVER WHATEVER SEXUAL TENSION-" Mettaton swiftly slapped a hand over Papyrus' mouth and awkwardly smiled.

"Papyrus, shhhh, that was supposed to stay between us sweetie," he muttered softly. "Sorry about that darling, so what do you say Frisk?"

Frisk awkwardly coughed and made an attempt to agree with Sans' opinion, sharing a bed would not be the best call, but one glance at Mettaton's face and she knew their was no way she was getting out of this situation. "Might as well make the best out of this, right Sans?" She laughed uncomfortably but Sans just glared down at her with loathing in his eyes.

"Sure," he hissed out with his jaw locked.

"PERFECT, EVERYTHING IS SETTLED! LETS ALL GO TELL ALPHYS THE GREAT NEWS!" Papyrus shouted, practically skipping towards Alphys' lab. Hesitantly, Mettaton turned to follow, leaving Sans and Frisk alone.

\-----

Frisk and Sans continued to walk side by side at a slow pace for a few moments before Sans decided to speak up.

“So, is Monster Kid a rebound thing or are you just a whore?”

Frisk sucked in a sharp breath and stopped dead in her tracks. She shot as much malice as she could towards him. “Fuck you. Are you jealous or are you just a dick? I'm not a whore, Monster Kid actually _likes_ me.”

Sans chuckled sarcastically and sauntered towards her, hands in his pockets. “I don’t believe you. If I kissed you right now, would you push me away?” Sans smirked, inching closer to her face.

“That's not fair, you know how I feel about you. But I-I would push you away, then I'd tell T-Toriel.” Frisk squeaked.

“What would she do? We aren't even dating,” Sans heatedly blurted out. The truth is out in the open but he couldn't find himself to care. He could feel radiating waves of fury exiting his body.

Frisk felt her jaw drop, disbelief dripping from her voice. “Are you fucking kidding me with this bullshit? Why did you tell me that in the first place then!? Do you think this is a game? Do you enjoy seeing me like this?”

Sans suddenly became too aware of his face heating up under Frisk's tempered gaze. He locked his eyes on his feet as he kicked a rock off to the side. “No! I...because you, Frisk, are perfect. Too perfect for a weird guy like me...”

“ _What_?! You're telling me this whole thing was because you're insecure?” Frisk face-palmed, grumbling into her hand a quick, ' _Are you freaking kidding me right now._ ' “Sans, you are perfect, in every single way. That's why I love you, you dolt.”

Sans grinned, pried her hand away from her face, and ran his fingers through her short hair, rewarding him with a soft shudder from Frisk. "May I?" Sans questioned, gesturing to kiss her and she let out a faint nod. A cyan pair of lips formed just as their lips caressed and a sharp fireworks erupted in both their bodies. The kiss went from sweet to passionate in a second as a cyan tongue manifested and gently entered her mouth. Instead of her jerking away, her own tongue fought its way in his mouth and, for a second, all his fears withered. She really did love him. But for how long? Frisk brought her hand to his skull and rubbed his jaw with her thumb earning her a soft moan and a cyan blush on Sans' cheekbones. He wanted this moment to last forever but it couldn't. Frisk gently pulled back and smiled.

"I love you Sans."

' _No more being a pussy Sans._ ' "I love you too Frisk, I really really do."

Frisk entwined their fingers and lead Sans to Alphys lab. When they reached the structure and stepped through the open door, Frisk let go of Sans hand. It was dark, the only light illuminating the room coming from a small TV screen. Mettaton, Papyrus, Alphys, and Undyne were all watching Mew Mew Kissy Cutie, Alphys’ favorite movie. Mettaton and Papyrus were flinging small pieces of popcorn at each other, almost going full out war, while Alphys' and Undyne were holding hands, murmuring sweet nothings to each other. Frisk glanced over at Sans, who was watching the scene with a heavy longing, as if he could never posses an easy-going relationship like them.

Frisk smirked to herself, knowing just what would lift his spirits. "Hey Sans?" she asked while poking his forearm.

"Hm?"

"What did one olive say to the other?"

Sans was in a trance, still distracted by the scene before him. "Hmm?...I uh... I dunno?"

Frisk braced herself before delivering the punch line. "Olive you."

Sans, shocked, slowly peered over at Frisk, her face housing the cheesiest smile he has ever seen. He playfully glared at her, trying to keep himself from grinning as a snicker began to bubble to the surface. Sans broke as full blown laughter erupted from his being, filling the entire room. "Oh my gods Frisk that was genius!" He hunched over nearly crying.

Frisk covered her mouth, giggling to herself. “Jeez, it wasn't that funny you dork. Calm down!" Frisk finally got herself situated from her giggle fit. “You know l do love you though.”

"Kiss me you fool."

The both giggled once more as they kissed before hearing a loud gasp from Mettaton.

"My goodness gracious! A love triangle! This is perfect!" Mettaton glimpsed over at Frisk, “This has been quite a busy day for you, hasn't it?”

They had a lot of explaining to do.


End file.
